| Polytetrafluoroethylene(PTFE)is an excellent solid lubricant with low friction coefficient and self-lubricating performance,but the poor wear resistance and mechanical properties restrict its application.In order to improve the mechanical and tribological properties of PTFE,the traditional method is to use reinforcement filling or blending modification.The single enhancement method often fails to obtain the ideal performance,therefor in this article,we combined these two reinforcement methods and used carbon fiber(CF)to reinforce the resin blend of Polyether etherketone(PEEK)and PTFE to achieve the purpose of improving the friction and mechanical properties of the material.Compared with the traditional short fiber reinforced materials,continuous fibers can effectively improve the strength of friction materials;The pre-impregnation of CF can be realized by using fabric that is woven by CF and resin fiber to prepare composites,which can improve the integrity and interfacial bonding strength.Therefore,in this experiment,the plain weave fiber fabrics were obtained by CFs,PTFE fibers and PEEK fibers;and then,the continuous CF-reinforced PTFE/PEEK composite materials were prepared by compression molding process;finally,the friction properties and mechanical properties of the samples were analyzed by means of friction experiment and computer simulation.We tested the thermal properties of the raw materials and made a series of comparative experiments to explored the molding process parameters: 345o C molding temperature,0.5 MPa molding pressure,[0/90]2 layering angle,alternate layer with fabric and mixed resin powder.The effect of material composition and friction conditions on the friction properties of laminated plates was studied by friction experiments.Based on the wear surface morphology,the friction mechanism was analyzed.Friction experiments confirmed that the addition of CF and PEEK can reduce the wear rate of the materials and extend the usage time;At the same time,the material will show the better wear resistance When we weave resin fibers into a bundle to make preforms,keep the CF orientation perpendicular to the sliding direction,control wt CF% in materials between 10%-15% and wt PEEK%/wt PTFE% between 0.50-1.25.No.2.6.1 laminate has the lowest wear rate,which is 1.69×10-7mm3/nm.The material has low friction coefficient under high load and low sliding speed,and low wear rate under low load and low friction speed,extending the friction time can reduce the wear rate.There are many flaky grinding chips and gullies on the surface of the wear morphology,so it is speculated that the friction mechanism is adhesive wear and abrasive wear.The macroscopic mechanical properties of the material,compatibility of the system and the adsorption of the resin abrasive debris were studied by Finite element simulation and molecular calculation to analyze the friction behavior of the material.The simulation experiment shows that decreasing the content of PTFE and increasing the content of CF can improve the tensile property,bending property and hardness of the material,but the excessive CF content may cause abrasive wear and decrease wear resistance.Molecular dynamics experiments have confirmed that when the wt PTFE% in the resin system is between 20% and 40%,the compatibility of the system is poor,but it does not reduce the friction performance obviously.The grinding chip adsorption experiment showed that PEEK was more conducive to adsorb on the metal surface,so it was speculated that the content of PEEK in the transfer film is higher than that in the grinding chips. |
PDF Full Text Request